Short description: Molecular structure having atoms at the centre and corners of a pentagonal bipyramid
| Pentagonal bipyramidal molecular geometry |
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| Examples | IF 7, ZrF 73-
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| Point group | D5h |
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| Coordination number | 7 |
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| Bond angle(s) | 90°, 72° |
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| μ (Polarity) | 0 |
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Structure of iodine heptafluoride, an example of a molecule with the pentagonal-bipyramidal coordination geometry.
In chemistry, a pentagonal bipyramid is a molecular geometry with one atom at the centre with seven ligands at the corners of a pentagonal bipyramid. A perfect pentagonal bipyramid belongs to the molecular point group D5h.
The pentagonal bipyramid is a case where bond angles surrounding an atom are not identical (see also trigonal bipyramidal molecular geometry).[1] This is one of the three common shapes for heptacoordinate transition metal complexes, along with the capped octahedron and the capped trigonal prism.[2][3]
Pentagonal bipyramids are claimed to be promising coordination geometries for lanthanide-based single-molecule magnets, since (a) they present no extradiagonal crystal field terms, therefore minimising spin mixing, and (b) all of their diagonal terms are in first approximation protected from low-energy vibrations, minimising vibronic coupling.[4]
Examples
- Iodine heptafluoride (IF7) with 7 bonding groups
- Rhenium heptafluoride (ReF7)
- Peroxo chromium(IV) complexes, e.g. [Cr(O2)2(NH3)3] where the peroxo groups occupy four of the planar positions.
- ZrF3−7 and HfF3−7[5][6]
References
- ↑ Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5
- ↑ Roald. Hoffmann; Barbara F. Beier; Earl L. Muetterties; Angelo R. Rossi (1977). "Seven-coordination. A molecular orbital exploration of structure, stereochemistry, and reaction dynamics". Inorganic Chemistry 16 (3): 511–522. doi:10.1021/ic50169a002.
- ↑ Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN:0-19-855370-6
- ↑ Duan, Yan; Rosaleny, Lorena E.; Coutinho, Joana T.; Giménez-Santamarina, Silvia; Scheie, Allen; Baldoví, José J.; Cardona-Serra, Salvador; Gaita-Ariño, Alejandro (2022-12-09). "Data-driven design of molecular nanomagnets" (in en). Nature Communications 13 (1): 7626. doi:10.1038/s41467-022-35336-9. ISSN 2041-1723. PMID 36494346. Bibcode: 2022NatCo..13.7626D.
- ↑ Kaupp, Martin (2001). ""Non-VSEPR" Structures and Bonding in d(0) Systems". Angew Chem Int Ed Engl 40 (1): 3534–3565. doi:3.0.CO;2-#">10.1002/1521-3773(20011001)40:19<3534::AID-ANIE3534>3.0.CO;2-#. PMID 11592184.3.0.CO;2-#&rft_id=info:pmid/11592184&rfr_id=info:sid/en.wikibooks.org:Physics:Pentagonal_bipyramidal_molecular_geometry">
- ↑ Zhenyang Lin; Ian Bytheway (1996). "Stereochemistry of Seven-Coordinate Main Group and d0 Transition Metal Molecules". Inorganic Chemistry 35 (3): 594–603. doi:10.1021/ic950271o.
External links
- [1] – Images of IF7
- 3D Chem – Chemistry, Structures, and 3D Molecules
- IUMSC – Indiana University Molecular Structure Center
Molecular geometry (VSEPR) |
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| Coordination number 2 | |
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| Coordination number 3 |
- Trigonal planar
- Trigonal pyramidal
- T-shaped
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| Coordination number 4 |
- Tetrahedral
- Square planar
- Seesaw
|
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| Coordination number 5 |
- Trigonal bipyramidal
- Square pyramidal
- Pentagonal planar
|
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| Coordination number 6 |
- Octahedral
- Trigonal prismatic
- Pentagonal pyramidal
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| Coordination number 7 |
- Pentagonal bipyramidal
- Capped octahedral
- Capped trigonal prismatic
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| Coordination number 8 |
- Square antiprismatic
- Dodecahedral
- Bicapped trigonal prismatic
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| Coordination number 9 |
- Tricapped trigonal prismatic
- Capped square antiprismatic
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